Date   : Sat, 18 Jul 2009 14:08:37 +0100
From   : samwise@... (samwise)
Subject: Master Ethernet upgrade

> Ah, you might be able to quickly clear up a question I've had for ages...
>
> Ethernet hub.
> Ethernet router.
>
> What's the difference? Both are boxes with a lot of RJ45s on to which
> you connect a bunch of computers...

The basic difference is that there is no intelligence in a hub.  All
packets that come into the hub are immediately broadcast out on all
the other ports and the devices attached to the hub are expected to
sort through and only take action on packets addressed to them.  This
allows you to capture the packets going to other machines on the
network - a useful debugging tool and also a security risk, depending
on the scenario.

A router learns which machines are attached to which port and after an
initial burst of traffic, will automatically route each of the
addressed packets to the correct port - which means devices on other
ports won't see the communications.  This is more secure and can
increase the throughput on the network ...

Peter.